Biochemical changes are frequently seen in patients with sarcoidosis and may reflect abnormalities in different components of the disease process, such as macrophage activation and granuloma formation, lymphocyte activation and proliferation, or the turnover of extracellular matrix proteins (Table 1)

In general, biochemical markers in sarcoidosis are closely related to immunologic abnormalities and therefore connected with the activity of the disease. The markers can be measured in serum, reflecting whole-body concentration, or in BAL fluid, more precisely indicating abnormalities in the alveolar compartment. Finally, they have been claimed to be at least partially useful in the clinical field, as diagnostic aids, as indicators of disease activity, or as factors predicting prognosis.

This review covers the current knowledge about the origin and pathophysiologic and clinical roles of biochemical changes in sarcoidosis.